Targeted gene deletion and phenotypic analysis of the Drosophila melanogaster seminal fluid protease inhibitor Acp62F.

Internally fertilizing organisms transfer a complex assortment of seminal fluid proteins, a substantial fraction of which are proteolysis regulators. In mammals, some seminal protease inhibitors have been implicated in male infertility and these same molecular classes of protease inhibitors are also found in Drosophila seminal fluid. Here, we tested the reproductive functions of the Drosophila melanogaster seminal fluid protease inhibitor Acp62F by generating a precise deletion of the Acp62F gene. We did not detect a nonredundant function for Acp62F in modulating the egg laying, fertility, remating frequency, or life span of mated females. However, loss of Acp62F did alter a male's defensive sperm competitive ability, consistent with the localization of Acp62F to sperm storage organs. In addition, the processing of at least one seminal protein, the ovulation hormone ovulin, is slower in the absence of Acp62F.